[libc-commits] [libc] [libc] Basic implementation of crt0 (PR #146863)

[Victor Campos via libc-commits]

================
@@ -1,11 +1,70 @@
+function(add_startup_object name)
+  cmake_parse_arguments(
+    "ADD_STARTUP_OBJECT"
+    "ALIAS" # Option argument
+    "SRC"   # Single value arguments
+    "DEPENDS;COMPILE_OPTIONS" # Multi value arguments
+    ${ARGN}
+  )
+
+  get_fq_target_name(${name} fq_target_name)
+  if(ADD_STARTUP_OBJECT_ALIAS)
+    get_fq_deps_list(fq_dep_list ${ADD_STARTUP_OBJECT_DEPENDS})
+    add_library(${fq_target_name} ALIAS ${fq_dep_list})
+    return()
+  endif()
+
+  add_object_library(
+    ${name}
+    SRCS ${ADD_STARTUP_OBJECT_SRC}
+    COMPILE_OPTIONS ${ADD_STARTUP_OBJECT_COMPILE_OPTIONS}
+    ${ADD_STARTUP_OBJECT_UNPARSED_ARGUMENTS}
+    DEPENDS ${ADD_STARTUP_OBJECT_DEPENDS}
+  )
+  set_target_properties(
+    ${fq_target_name}
+    PROPERTIES
+      OUTPUT_NAME ${name}.o
+  )
+endfunction()
+
 add_entrypoint_object(
   init
   SRCS
     init.cpp
+  HDRS
+    init.h
 )
 
 add_entrypoint_object(
   fini
   SRCS
     fini.cpp
+  HDRS
+    fini.h
 )
+
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_ARCHITECTURE})
+  add_subdirectory(${LIBC_TARGET_ARCHITECTURE})
+else()
+  message(WARNING "Cannot build 'crt1.o' for ${LIBC_TARGET_ARCHITECTURE} yet.")
+  return()
+endif()
+
+add_startup_object(
+  crt1
+  ALIAS
+  DEPENDS
+  .${LIBC_TARGET_ARCHITECTURE}.crt1
+)
+
+add_custom_target(libc-startup)
+set(startup_components crt1)
+foreach(target IN LISTS startup_components)
----------------
vhscampos wrote:

If `startup_components` only has one element, a for loop doesn't look necessary.

https://github.com/llvm/llvm-project/pull/146863